1. Field of the Invention
The present invention relates to controlled reluctance, eddy-current generator type material inspection apparatus and methods, and more particularly to eddy-current probes or tools which are especially adapted for inspecting metal tubing, fastener holes, rods and similar geometries.
2. Cross-Reference to Related Application
The present invention is related to the invention described in copending application Ser. No. 741,666, filed Nov. 15, 1976, and entitled EDDY-CURRENT FLUX GENERATOR FOR TESTING OR MATERIAL, in the both inventions involve the use of high and low reluctance materials to concentrate the reluctance of exciting coils in the material to be tested and to control the spatial extent of the generated eddy currents.
3. Discussion of the Prior Art
The aforementioned application Ser. No. 741,666 commences with a quite detailed discussion of eddy-current testing techniques and a comparison of the invention to which such application relates with specific prior art devices. Application Ser. No. 741,666 also includes a quite detailed explanation of the use of high and low reluctance materials together to (1) concentrate the reluctance of the eddy-current generator in the material to be tested and (2) control the spatial extent and shape of generated eddy currents. For background purposes, reference should be made to the complete disclosure of U.S. application Ser. No. 741,666, the contents of which are hereby incorporated herein by this specific reference.
U.S. application Ser. No. 741,666, the several patents mentioned therein, and the prior art that was cited and considered by the Patent Office, both with respect to such application and its predecessor (Ser. No. 538,955, now abandoned), should be consulted for the purpose of properly evaluating the subject invention and putting it into proper perspective.
Particular patents which should be considered are U.S. Pat. No. 3,430,134, granted Feb. 25, 1969 to John J. Flaherty and Richard M. Soble, and entitled Weld Tracker System Having Magnetically Isolated Pickup Coils and U.S. Pat. No. 3,840,802, granted Oct. 8, 1974 to Phillip L. Anthony. These patents involve the use of a plurality of eddy-current generators in a single probe or sensing apparatus.